HONG KONG (Reuters) – Young people thronged the streets of Hong Kong this week, keen to test Pokemon GO, a new smartphone game backed by Japan’s Nintendo &lt;7974.T&gt;, capturing monsters at sites of the city’s 2014 democracy protest, known as the Umbrella Revolution.

The game launched in the Asian financial hub this week after becoming an unexpected hit in countries from Spain to New Zealand, helping to double Nintendo’s value since its debut in the United States this month.

The DailyBrief

Must-reads from across Asia - directly to your inbox

Created by Nintendo, Niantic and Pokemon, the game plays out in what is known as augmented reality, by tapping users’ GPS applications to spawn Pokemon, or pocket monsters, against the backdrop of the real environment.

People play “Pokemon Go” during lunch time outside an office building after the augmented reality mobile game launched in the city in Hong Kong, China, July 26, 2016. REUTERS/Bobby Yip

Users in the Chinese territory logged on immediately after Monday’s launch and stayed glued to their phones throughout Tuesday, playing around office blocks, shopping malls and on underground trains.

The game features spots such as the “Lennon” wall, a main site of democracy protests in 2014, when thousands of people took to the streets for more than two months to demand that Beijing allow full democracy in the former British colony.

“The movement only lasted for months but the game makes it special,” said university student Cathy Chan, 20, adding that the wall, covered in democracy missives and named in tribute to former Beatle John Lennon, represented Hong Kong and served as a record of the movement. “It is really special.”

People play “Pokemon Go” at a shopping mall after the augmented reality mobile game launched in the city in Hong Kong, China, July 26, 2016. REUTERS/Bobby Yip

The location features in the game as a “gym”, where users can fight battles to boost their scores.

In selecting its sites, the game uses photographs uploaded over the past few years by players of a previous Niantic game, Ingress, which is still played by followers in Hong Kong.

Although Pokemon GO has not yet launched in China, Hong Kong travellers can use roaming network facilities to access the game in its southern city of Shenzhen, as did some in the gambling hub of Macau.

The buzz spurred Hong Kong phone companies to offer special data plans for game enthusiasts.

People play “Pokemon Go” on a street after the augmented reality mobile game launched in the city in Hong Kong, China, July 26, 2016. REUTERS/Bobby Yip

Some office workers said they played Pokemon GO on their lunch breaks and resumed immediately after work.

“When I walk back home and after supper, I also play it,” said one fan, Elaine Wan. “Actually, all my colleagues are around playing the game.”

China rules Hong Kong under a “one country, two systems” formula that allows wide-ranging autonomy and freedoms not enjoyed on the mainland.

The 2014 protests presented Beijing with one of its biggest political challenges since it crushed pro-democracy demonstrations in the Chinese capital in 1989.